Millimeter Wave Beamforming Calibration via Phase Codebooks

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Solution Overview

Problem

In millimeter wave communications, beamforming devices face significant challenges due to phase differences between antenna modules, leading to reduced equivalent isotropically radiated power (EIRP) and poor side-lobe levels, causing deviations from ideal beamforming patterns.

Innovation Solution

A calibration method and system that generates calibration codebooks based on reference codebooks and predetermined phase differences, using a processor, memory unit, baseband circuit, and antenna modules to adjust phase shifters and amplifiers, optimizing equivalent isotropically radiated powers (EIRP) and redirecting radiation patterns to match design specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If beamforming technology is used to increase communication range in millimeter wave applications, then communication range is improved, but phase differences between antenna modules cause deviation from ideal beamforming patterns

Engineering Contradiction:

Improvecommunication rangeVSAvoidbeamforming pattern accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing calibration before actual beamforming operations. The system pre-determines phase differences between antenna modules and stores correction data in codebooks, so that when beamforming is executed, the pre-calculated phase corrections are already available to maintain accurate beamforming patterns despite manufacturing variations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the phase parameters of individual antenna modules based on measured or predetermined phase differences. By adjusting these phase parameters through calibration and selecting appropriate codebooks, the system compensates for manufacturing tolerances and maintains accurate beamforming patterns while operating at millimeter wave frequencies

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If path change of 0.1 mm occurs in antenna module positioning, then manufacturing tolerance is acceptable, but phase difference of 36 degrees is caused between antenna modules

Engineering Contradiction:

Improveantenna module positioning toleranceVSAvoidphase difference accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent implements feedback by measuring the actual phase differences between antenna modules during calibration and using this information to select or generate appropriate codebooks. The system continuously monitors beamforming performance and adjusts phase corrections based on measured deviations, creating a closed-loop system that compensates for positioning tolerances

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary calibration to determine and store phase correction data before actual beamforming operations. This pre-characterization of phase differences allows the system to compensate for manufacturing tolerances without requiring ultra-precise positioning during production

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If phase difference exists between antenna modules, then beamforming operation is simplified, but equivalent isotropically radiated power (EIRP) is reduced and side-lobe levels deteriorate

Engineering Contradiction:

Improvebeamforming operation simplicityVSAvoidequivalent isotropically radiated power

Core Design Contradiction:

Ease of operationVSPower

Solution Approach 1:

The patent changes the phase parameters of antenna modules based on calibration data to optimize beamforming performance. By adjusting these phase parameters according to predetermined or measured phase differences, the system maximizes EIRP and minimizes side-lobe levels while maintaining operational simplicity through automated codebook selection

Inventive Principle:

Principle #35Parameter changes

4Manufacturing precision

If calibration is performed to correct phase differences, then beamforming performance is improved, but system complexity and calibration time are increased

Engineering Contradiction:

Improvebeamforming pattern accuracyVSAvoidcalibration system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs calibration operations in advance and stores the results in codebooks for later use. This preliminary characterization eliminates the need for complex real-time calibration during beamforming operations, reducing system complexity while maintaining high beamforming accuracy through pre-computed correction data

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11239552B2Beamforming device, calibration method and calibration system for the same

Publication Date: 2022.02.01 WISTRON NEWEB CORP

AI summary

A beam forming device, a calibration method and a calibration system using the same are provided. The beam forming device includes a processor, a memory unit, a baseband circuit, and a plurality of antenna modules. The antenna modules each includes multiple antenna elements, and multiple phase shifters and multiple of amplifiers respectively corresponding to the antenna elements. The memory unit stores a reference codebook, a plurality of calibration codebooks and instructing data, each of the plurality of calibration codebooks includes a plurality of records of calibration control data divided by a plurality of target patterns, and a plurality of predetermined phase differences that are different from each other respectively existed between the plurality of calibration codebooks and the reference codebook. The instruction data is used for instructing the beamforming device to use one of the reference codebook and the plurality of calibration codebooks in transmitting and receiving signals.